Several improvements to the formatting of static initializers.

1. Never avoid bin packing in static initializers as this can
   lead to terrible results.
2. If an element has to be broken over multiple lines, break after
   the following comma.

This should be a step forward, but there are still many cases
especially with nested static initializers that we handle badly.
More patches will follow.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@174061 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 39 insertions, 11 deletions

diff --git a/lib/Format/Format.cpp b/lib/Format/Format.cpp
index 08ea8e97de..2a606974e5 100644
--- a/lib/Format/Format.cpp
+++ b/lib/Format/Format.cpp
@@ -229,7 +229,8 @@ public:
     LineState State;
     State.Column = FirstIndent;
     State.NextToken = &RootToken;
-    State.Stack.push_back(ParenState(FirstIndent + 4, FirstIndent));
+    State.Stack.push_back(ParenState(FirstIndent + 4, FirstIndent,
+                                     !Style.BinPackParameters));
     State.VariablePos = 0;
     State.LineContainsContinuedForLoopSection = false;
 
@@ -298,10 +299,11 @@ private:
   }
 
   struct ParenState {
-    ParenState(unsigned Indent, unsigned LastSpace)
+    ParenState(unsigned Indent, unsigned LastSpace, bool AvoidBinPacking)
         : Indent(Indent), LastSpace(LastSpace), AssignmentColumn(0),
           FirstLessLess(0), BreakBeforeClosingBrace(false), QuestionColumn(0),
-          BreakAfterComma(false), HasMultiParameterLine(false) {
+          AvoidBinPacking(AvoidBinPacking), BreakAfterComma(false),
+          HasMultiParameterLine(false) {
     }
 
     /// \brief The position to which a specific parenthesis level needs to be
@@ -334,7 +336,15 @@ private:
     /// \brief The column of a \c ? in a conditional expression;
     unsigned QuestionColumn;
 
+    /// \brief Avoid bin packing, i.e. multiple parameters/elements on multiple
+    /// lines, in this context.
+    bool AvoidBinPacking;
+
+    /// \brief Break after the next comma (or all the commas in this context if
+    /// \c AvoidBinPacking is \c true).
     bool BreakAfterComma;
+
+    /// \brief This context already has a line with more than one parameter.
     bool HasMultiParameterLine;
 
     bool operator<(const ParenState &Other) const {
@@ -350,6 +360,8 @@ private:
         return BreakBeforeClosingBrace;
       if (QuestionColumn != Other.QuestionColumn)
         return QuestionColumn < Other.QuestionColumn;
+      if (AvoidBinPacking != Other.AvoidBinPacking)
+        return AvoidBinPacking;
       if (BreakAfterComma != Other.BreakAfterComma)
         return BreakAfterComma;
       if (HasMultiParameterLine != Other.HasMultiParameterLine)
@@ -444,6 +456,9 @@ private:
         State.Column = State.Stack[ParenLevel].Indent;
       }
 
+      if (Previous.is(tok::comma) && !State.Stack.back().AvoidBinPacking)
+        State.Stack.back().BreakAfterComma = false;
+
       if (RootToken.is(tok::kw_for))
         State.LineContainsContinuedForLoopSection = Previous.isNot(tok::semi);
 
@@ -499,6 +514,7 @@ private:
         State.Stack.back().LastSpace = State.Column;
       else if (Previous.ParameterCount > 1 &&
                (Previous.is(tok::l_paren) || Previous.is(tok::l_square) ||
+                Previous.is(tok::l_brace) ||
                 Previous.Type == TT_TemplateOpener))
         // If this function has multiple parameters, indent nested calls from
         // the start of the first parameter.
@@ -509,7 +525,7 @@ private:
     if (Newline && Previous.is(tok::l_brace))
       State.Stack.back().BreakBeforeClosingBrace = true;
 
-    if (!Style.BinPackParameters && Newline) {
+    if (State.Stack.back().AvoidBinPacking && Newline) {
       // If we are breaking after '(', '{', '<', this is not bin packing unless
       // AllowAllParametersOfDeclarationOnNextLine is false.
       if ((Previous.isNot(tok::l_paren) && Previous.isNot(tok::l_brace) &&
@@ -538,6 +554,17 @@ private:
       State.Stack.back().FirstLessLess = State.Column;
     if (Current.is(tok::question))
       State.Stack.back().QuestionColumn = State.Column;
+    if (Current.is(tok::l_brace) && Current.MatchingParen != NULL &&
+        Current.Children[0].isNot(tok::l_brace) &&
+        !Current.MatchingParen->MustBreakBefore) {
+      AnnotatedToken *End = Current.MatchingParen;
+      while (!End->Children.empty() && !End->Children[0].CanBreakBefore) {
+        End = &End->Children[0];
+      }
+      unsigned Length = End->TotalLength - Current.TotalLength + 1;
+      if (Length + State.Column > getColumnLimit())
+        State.Stack.back().BreakAfterComma = true;
+    }
 
     // If we encounter an opening (, [, { or <, we add a level to our stacks to
     // prepare for the following tokens.
@@ -545,16 +572,16 @@ private:
         Current.is(tok::l_brace) ||
         State.NextToken->Type == TT_TemplateOpener) {
       unsigned NewIndent;
+      bool AvoidBinPacking;
       if (Current.is(tok::l_brace)) {
-        // FIXME: This does not work with nested static initializers.
-        // Implement a better handling for static initializers and similar
-        // constructs.
-        NewIndent = Line.Level * 2 + 2;
+        NewIndent = 2 + State.Stack.back().LastSpace;
+        AvoidBinPacking = false;
       } else {
         NewIndent = 4 + State.Stack.back().LastSpace;
+        AvoidBinPacking = !Style.BinPackParameters;
       }
-      State.Stack.push_back(ParenState(NewIndent,
-                                       State.Stack.back().LastSpace));
+      State.Stack.push_back(ParenState(NewIndent, State.Stack.back().LastSpace,
+                                       AvoidBinPacking));
     }
 
     // If we encounter a closing ), ], } or >, we can remove a level from our
@@ -611,7 +638,8 @@ private:
     // Trying to insert a parameter on a new line if there are already more than
     // one parameter on the current line is bin packing.
     if (NewLine && State.NextToken->Parent->is(tok::comma) &&
-        State.Stack.back().HasMultiParameterLine && !Style.BinPackParameters)
+        State.Stack.back().HasMultiParameterLine &&
+        State.Stack.back().AvoidBinPacking)
       return UINT_MAX;
     if (!NewLine && (State.NextToken->Type == TT_CtorInitializerColon ||
                      (State.NextToken->Parent->ClosesTemplateDeclaration &&